Default Tempered Glass Questions

First things first is this legit? or some cheap knockoff of the real stuff!

http://www.ebay.com/itm/Premium-Real...item5d48cb0407

second question when the glass is applied can it be ever taken off?

Sorry for the newb questions this is my first time applying a screen protector
Devices: Nexus 5 (Sold) 1X
Nexus 5
HTC One